The present invention relates to a method of correcting resolution drift of a quadrupole rod set mass analyser, a method of mass spectrometry and a mass spectrometer.
The resolution and mass accuracy of a quadrupole mass spectrometer (“QMS”) is susceptible to environmental factors such as temperature and humidity. When operated at unit mass resolution (approximately 0.7 Da FWHM) the resolution and mass position drift of modern QMS instruments is tolerable but at higher resolutions (e.g. 0.05 to 0.2 Da) the same degree of drift can become unacceptable.
It is known to use an external calibrant or reference compound which is commonly referred to as a “lock mass” to correct the mass accuracy of a Time of Flight (“ToF”) mass analyser.
However, as will be understood by those skilled in the art, mass accuracy is quite different from mass resolution.
It is desired to provided an improved method of mass spectrometry and mass spectrometer.